Firing mechanism for semi-automatic firearms and safety therefor



Feb. 12, 1952 c. H BENSON 2,585,620

FIRING MECHANISM FOR SEMI-AUTOMATIC FIREARMS AND SAFETY THEREFOR Filed April 14, 1945 2 SHEETS-SHEET l INVENTOR. Car] HBenson.

Arron/m Feb. 12, 1952 c. H. BENSON 2,585,620

FIRING MECHANISM FOR SEMI-AUTOMATIC FIREARMS AND SAFETY THEREFOR Filed A ril 14, 1945 2 SHEETSSHEET 2 INVENTOR Carl H.Bena'on.

ATTORNEY Patented Feb. 12, 1952 UNITED STATES PATENT OFFICE Carl H. Benson, New Haven, Conn, assignor to 0. F. Mossberg & Sons,- Inc., New Haven, Conn., a corporation of Connecticut Application April 14, 1945, Serums. 588,342

10 Claims. 1

This invention relates to improvements in firearms of the small arm type and more particularly to an improved cartridge firing mechanism for a firearm of the semi-automatic type.

In firearms of the semi-automatic type a reciprocating member is arranged in a receiver to engage and feed cartridges one at a time from a magazine into the chamber of a barrel and to be recoiled when the cartridge is fired, to extract the cartridge shell therefrom, to set the firing mechanism inoperative position, to again feed a cartridge into the chamber and to remain in battery position until the firing mechanism is released by a trigger, or the like, to fire the cartridge. To obviate the possibility of continuous, or unintentional, firing, due to a sustained pressure on the trigger, or if the trigger is not released quickly enough for the sear to engage its cooperating part of the firing mechanism, it is.

contemplated as one object of this invention to provide in a firearm the improved firing mechanism of this invention. The improved firing mechanism of this invention causes the sear to be automatically disconnected from the action of the trigger and be free to engage its cooperating part of the firing mechanism to prevent firing action until the trigger is sufliciently released to' assume its operative position in readiness to release the firing mechanism.

Another object of this invention is to provide in a firearm an improved firing mechanism hav ing a sear activating member which is actuated by the trigger and which is adapted to be acted upon by another part of the mechanism to prevent its' operative engagement with the sear until after the sear has engaged its cooperating part of the firing mechanism.

Still another object is to provide in a firing mechanism of a firearm means to prevent the release of the sear from its cooperating part of 1 said mechanism when the cartridge engaging member has not fully inserted a cartridge in the mechanism which will be relatively inexpensive to manufacture, simple in construction, practical, and very efiicient and durable in use.

With these and other objects in view, which will appear as the description proceeds, there has been illustrated in the accompanying drawings 2 one form in which the invention may be embodiedin practice In the drawings:

Figure 1 is aside view of the assembled opera tive parts of a firearm embodying the features and principles of this invention, the barrel being shownbroken oil and the usual stock omitted fol-the sake of clearness; b 7

Figure 2 is a longitudinal sectional view through the receiver to show the firing mechanism therein, which mechanism is shown with its parts in position to be actuated to fire a cartridge disposed in the chamber of the barrel;

Figure 3 is a partially broken away view similar to Figure 2 but showing the firing mechanism parts in the position assumed thereby as a cartridge is fired, i I 7 Figure 4 is an enlarged cross-sectional view taken on the line 4-4 of Figure 2; a

Figure 5 is an enlarged cross-sectional view taken on the line 5-5 of Figure 1;

Figure 6 is an enlarged cross-sectional view taken on the line 6-6 of Figure 1 when certain parts thereof are in position to lock the action in safety position; I

Figure 7 is anenlarged sectional view similar to Figure 2, and

Figure 8 is a cross-sectional view taken on the line ti -8 of Figure 7.

Referring now to the drawings wherein like reference numerals designate like parts throughout the several views,- the numeral ll denotes a barrel having a bore l2- and a cartridge chamber 13.- The barrel II has its breech end suitably secured in the forward end of a receiver [4 which is shown tubular in form and has its rear end closed by a removable head 15 screw-threaded therein; In this'instance abox-shaped magazine [6 is provided and is suitably arranged and posi tionecl to feed cartridges upwardly, in the usual manner, into the path of a bolt H to be engaged thereby and pressed into the cartridge chamber i3, the magazine passing through the receiver 14 and having its upper edge lying in a cut 46 provided in thebolt I]. The bolt IT in this instance is cylindrical in form and is constantly urged into in-battery position by a coiled spring I8 reacting between the bolt I! and the head 15. I A firing pin I3 is slidably mounted in the bolt I7 and has a point 2! adapted to strike the cartridge primer to the thecartridge when the rear end of the pin I9 is forcibly struck by a hammer 2 2 which-is. slid-ably mounted in the receiver to the rear ofthe bolt". The firing pin I9 is urged rearward-1y to protrude from the rear end of the bolt into the path of the hammer 22 by a spring 23 reacting between the bolt l1 and a pin 24 in the firing pin l9. An extractor 25 of the usual form is carried by the bolt I! in position to engage and extract the fired cartridge shell from the chamber l3 and direct it outwardly through an opening 26 provided in the receiver M in the usual manner.

The bolt I? may be manually retracted by a stud 26 which has a stem 21 extending through the receiver and into an opening 28 provided in the bolt I! to receive it. The stem 21 of the stud 26 (see Figures and 6) is provided with a flat narrowed portion 28 adapted to slidingly fit in a slot 29 in the receiver side and to prevent turning of the bolt I! in the receiver l4 and guide it axially therein- The receiver |4 has an opening 3|, Figure 1, provided therein in connection with the slot 29 and positioned slightly to the rear of the extreme possible position of the stud 26 when the bolt I1 is retracted to its full possible rearward position when the head I5 is in place. By removing the receiver head l5 the bolt 7 may be retracted beyond said possible rearward position to permit removal of the stud 26 therefrom and thus removal of the bolt ll from the receiver I4 through the rear end thereof. When the parts are in assembled condition as shown in Figures 1, 2; and 3, the stud 26 cannot possibly be removed through the opening 3| and be mislaid, or lost. Spaced rearwardly from the position assumed by the stud 26 when the bolt li is in battery position the receiver is provided with a shallow counterbore 32 into which a full diameter portion 33 of the stud may be pressed to hold the bolt H in sufiicient out-of-battery position to prevent the engagement of the firing pin point 2| to strike the cartridge primer should the same be actuated, and to hold the bolt IT into a position whereby actuation of the firing mechanism is prevented as will be described hereinafter. The structure above described provides one of the safety features of this invention.

The hammer 22 is constantly under the urge of a coiled spring 34 reacting between the hammer 22 and the flange 35 of a flanged sleeve 36. The flange 35 normally rests against the forward end of the head l5 with the sleeve portion 36 extending forwardly therefrom. The forward end of the sleeve 36 is crimped inwardly to form a rearwardly directed annular shoulder 31 adapted to be engaged by a collar 38 formed on the rear end of a rod 39 secured to and extending rearwardly from the bolt IT to retain these parts together when they are disassembled from the receiver l4 after removal of the head IS.

The hammer 22 is cylindrical in form and has an opening 4| therethrough to allow passage of the spring l8 and the rod 39.' An enlarged portion 42 of the opening 4| provides for the spring 34 and forms a shoulder 43 for the spring 34 to seat against. The hammer 22 is reduced in diameter intermediate its ends to form an annular forwardly directed shoulder 44 to form an annular sear notch and the rear end thereof is beveled at its outer edge as at 45. The reduced diameter portion 46 of the hammer 22 extends forwardly a desired amount and the periphery of the hammer is then tapered outwardly as at 47 to its full diameter the forward end edgebeing beveled as at 48.

A sear 49 pivoted to the receiver on a pin 5| has an arm 52 extending'rearwardly. A sear catch 53 is formed on the rear end of the arm 52 to snap into hammer holding engagement with hammer 22 in front of and against the annular sear notch, or shoulder, 44 provided on the hammer 22, due to the tension of the forward end 54 of a leaf spring secured to the receiver by a screw 55. The sear 49 has a forwardly directed arm 56 which extends through .a slot 51 provided in the receiver [4 and has an upturned end 58 adapted to engage against a full diameter portion 36 of the peripheral surface of the bolt disposed between the relief cut 60 and the relief cut 50 (see dotted lines in Figure 2) when the bolt I1 is not in full battery position to prevent the sear catch 53 from being releasd from the sear notch 46. When in battery position the sear arm end 56 is free to swing upwardly by the provision of a relief cut 60 in the rear end of the bolt IT.

The sear 49 is provided with a rearwardly directed shoulder 6| forming a connector notch and against which the forward end 62 of a connector 63 may engage to swing the sear 49 upon the pin 5| when the connector 63 is pressed forwardly. The connector 63, in this instance, is of pressed metal and U-shaped in cross-section, the arms of the U -shape straddling the sear 49. The arms of the U-shaped connector 63 adjacent its forward end 62 are extended upwardly in the hammer 22. The rear end of the connector 63 is pivoted to the upper end of a trigger 65 .on a pin 66 and is acted upon by the rear end 61 of the leaf spring to urge the connector forward end 62 into engagement with the sear 49.

The trigger 65 is pivoted to downwardly extending arms of a bracket 66 on a pin 69. A spring 10 coiled about the pin 69 has an end in engagement with the trigger 65 and an end 1| with the receiver through the head of a screw 12 and is tensioned to constantly urge the lower finger engaging end 13 of the trigger 65 forwardly and its upper end rearwardly. The screw 12 with the screw 55 clamps the bracket 68 to the receiver I4 and secures a spring 14 to the bracket in position to engage the knurled periphery of the head |5 to releasably lock it in position.

Assuming that the firearm is unloaded, the parts are in position as shown in Figure 3, and a magazine of cartridges is in position, the firearm may be initially loaded by drawing back the bolt l4 by means of the stud 26. This action draws the hammer 22 back into cocked position with the sear catch 53 in engagement with the hammer 22 in the sear notch 44. The bolt I4 is then allowed to move forward into battery position under urge of the spring I 8 whereby a cartridge is drawn from the magazine I6 and inserted into the chamber l3 of the barrel The parts are now in the position illustrated in Figure 2 and ready to fire a cartridge.

Pressure is now applied rearwardly to the trigger 65, on the finger piece 13, rocking the trigger 65'on the pin 69 whereby the connector 63 is pressed forwardly, through the pin 66. The sear engaging end 62 of the connector 63 is in engagement with the sear 49 against the shoulder 6| and rocks the sear 49 on the pin 5| to release the sear catch 53 from the sear notch 44 in the hammer 22. the sear notch 44 causes the hammer 22 to move forwardly under urge of the hammer spring 34 and to sharply strike the protruding-end of the Release of the sear catch 53' from:

firing pin l9 and cause its point 2| to sharplystrike the cartridge primer to fire the cartridge in the barrel chamber 13-. If the bolt H was not in full battery position the sear end 58, during the above operation, will engage against the bolt and prevent release of the sear catch 53 from the notch 45.

The recoil action due to the firing of the cartridge retracts the bolt l7 and with it the hammer 22. When this action takes place the full diameter rear end of the hammer 22 engages the sear catch 53 and the sear 49 pivots on its pivot pin 5! to swing the sear end 58 upwardly and to allow for this movement the bolt is cut away on its bottom surface to provide a relief cut 50 into which the sear end 58 may swing. The sear 49 must also be free to pivot on the pin 5| in order that the sear catch 53 will catch in the sear notch 44 of the hammer 22 the instant the hammer is in sufficient retracted position for it to do so. The sear therefore must be free from any interference by the connector 63. To insure that such action is positive, the hammer 22 during its forward firing movement disengages the sear engaging end 62 of the connector from the notch- 6| in the sear 49 by its full diameter forward end acting on the ears 65 to swing the connector downwardly into the position shown in Figure 3. The sear end 52 under urge of the end 54 of the leaf spring is thus allowed to rock upwardly whereby the connector end 62 is held by the sear 49 against dropping into the notch 6|. When the hammer 22 is retracted and the trigger 65 is released to retract the connector 63, the sear end 52 rocks in front of the shoulder 44 and disposes the connector notch 6| in position to receive the connector end 62, and the parts are again in firing position.

If there is a cartridge in the chamber l3, or if it is desired to releasably prevent loading of the chamber when carrying the firearm, the stud 26 is pulled rearwardly to retract the bolt sufiiciently to allow the stud portion 33 to be pressed into the shallow counterbore 32. position the bolt l1 prevents the sear 49 from being rocked to have its sear catch 53 released from the notch 44, the forward end 58 engaging against the periphery of the bolt to prevent such movement. The same action of the bolt ll upon the sear end 58 takes place, forming another safety feature, whenever an obstruction, or other condition, is present to prevent the bolt I! assuming a full closed action position thus insuring that no cartridge will be fired unless it is being firmly held in the chambers 13 by the bolt [7.

By the provision of the above described improved firing mechanism and safety features in the structure of a firearm, efficient operation thereof is insured, the action being smooth and positive. The arrangement of the parts whereby the hammer and bolt with their operating springs may be simultaneously removed as a sub-assembly from the receiver is advantageous in that the said parts are not in danger of being lost, or mutilated, during disassembly. The construction and arrangement of the trigger, connector, and sear combination insures that unintentional, or continuous, firing action will not occur, should the trigger be sustained in firing position beyond the required interval of sear release.

It will be understood that the novel features and principles of this invention may be embodied in other specific forms without departing from When in such the spirit and essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative, and not restrictive, reference being had to the claims rather than to the foregoing description to indicate the scope of the invention.

Having thus fully disclosed the what is claimed as new and for what it is desired to secured Letters Patent, is:

1. In firing mechanism for a firearm, a receiver, a cartridge firing element, an element movable in the receiver to strike said firing element to fire a cartridge, said movable element having a sear notch, a scar engaging said movable element in said sear notch to releasably hold said element against movement, a trigger, a conhector attached to said trigger and releasably engaging said sear for transmitting movement of the trigger to the sear to release it from the sear notch in the movable element, and means on the connector extending into the pathof movement of said movable element, to be engaged by said movable element when it is released by the sear to release the connector from said sear.

2. In firing mechanism for a firearm, a receiver, a cartridge firing element, operable means for actuating said firing element, said operable means being movable lengthwise of said receiver, said means having a scar notch, a sear releasably engagable with said means in the sear notch therein to hold it, said sear having a notch,

means for releasing said actuating means from said sear including a swingable member releasably engageable with said sear in the notch therein, said swingable member having a portion lying in the path of movement of said element actuating means to be engaged by said element, when it is released, to move the swingable member out of engagement with the sear in the notch therein.

3. In a firearm, a receiver, cartridge firing mechanism including a bolt slidable in said receiver and carrying a firing pin, afirst member axially slidable in the receiver to strike said firing pin, a spring for actuating said member, said member having a scar notch, a spring pressed sear swinga-b-le to engage said member in the sear notch and hold said member against action by said spring, and a second member movable to engage and move said sear from engagement with said first member to release it, said second member having a portion extended into the path of movement of said first member to be engaged by the released first member to move the second member out of sear engaging position.

4. In a firearm, a receiver, cartridge firing mechanism including a bolt slidable in said re ceiver and carrying a firing pin, a first member movable axially in respect to said receiver to strike said firing pin, a spring for actuating said member in one direction, said first member having a sear notch, a pivoted sear adapted to enter the sear notch in said member and hold said member against actuation by said spring, a spring acting on said sear to urge it into the rear notch in said member, and a second member movable to engage and move said sear fromthe sear notch in said first member to release the first member, the second member having a portion disposed in the path of movement of the first member to be engaged by the released first member to move the second member out of sear engaging position.

5. In a firearm, a receiver, a bolt slidable in invention,

said receiver to dispose and hold a cartridge in firing position, cartridge firing mechanism in cluding a spring actuated first member movable axially in said receiver, a swingable sear having a first arm adapted to engage said member and retain it against spring action, said bolt having an upwardly directed first relief cut in its rear end, a full diameter portion forward of said first relief out, and a second relief cut directed upwardly and being disposed forward of said full diameter portion, and a second arm having an end portion positioned to engage said full diameter portion of said bolt when the latter is out of position to hold a cartridge in firing position and prevent swinging of the sear to move the first arm to release said member.

6. In a firearm, a receiver, a bolt slidable in said receiver, said bolt carrying a firing pin slidable lengthwise therein, a hammer slidable in said receiver to strike said firing pin to fire a cartridge, said hammer having an annular sear notch formed therein intermediate its ends, a sear pivoted to said receiver and having an arm extending into said receiver at one side of the pivot and a second arm extending into said receiver at the other side of the pivot, a catch on the end of the first mentioned sear arm to engage said hammer in the sear notch therein, said sear having a notch on the outer surface thereof, a trigger pivoted to said receiver, a connector pivoted at one end to the trigger and having its other end formed'to catch in the notch in said sear, spring means to urge said first sear arm into engagement with the notch in said hammer, spring means to urge said connector catch end into engagement with the notch in said sear, said bolt having a full diameter portion at its rear end disposed between two spaced apart relief cuts in its under surface adjacent its rear end positioned to be engaged by said second sear arm, when the bolt is not fully in cartridge firing position, to hold said sear against swinging movement on its pivot and thus prevent disengagement of said sear catch from said sear notch in said hammer.

7. In a firearm, a receiver, a bolt slidable in said receiver, said bolt carrying a firing pin slidable lengthwise therein, a hammer slidable in said receiver to strike said firing pin to fire a cartridge, said hammer having an annular sear notch formed therein intermediate its ends, a sear pivoted to said receiver and having an arm extending into said receiver, a catch on the end of said sear arm to engage said hammer in the sear notch therein, said sear having a notch on the outer surface thereof, a trigger pivoted to said receiver, a connector pivoted at one end to said trigger and having its other end formed to catch in the notch in said sear, said hammer having an annular portion forward of the sear notch therein, a part adjacent the sear catch end of said connector extending into the receiver into the path of movement of said hammer to be engaged by said annular portion on said hammer to move said sear catch end out of sear notch engaging position.

8. In firing mechanism for a firearm, a receiver, a cartridge firing element, a cylindrical hammer slidable in the receiver toward the firing element to strike it to fire a cartridge, said hammer having a sear notch, a sear pivoted to the receiver and releasably engaging said hammer in'the sear notch to hold it in non-operable position, a trigger, a connector having one end pivotally connected to the trigger and its other end engageable with the sear and being movable by the trigger to move the sear from the sear notch in the hammer, and an ear on the connector extending into the path of movement of the hammer to be engaged thereby when the hammer is released from engagement by the sear to disconnect the connector from the sear.

9. In firing mechanism for a firearm, a receiver, a bolt slidable in the receiver, a cartridge firing element slidable in the bolt, a cylindrical hammer slidable in the receiver toward the firing element to strike it to fire a cartridge, said hammer having a sear notch, a sear pivoted to the receiver and having an arm extending from the pivot point rearwardly into the receiver to releasably engage the hammer in the sear notch, another arm on thesear extending from the pivot point forwardly into the receiver, said bolt having a full diameter annular portion on its peripheral surface disposed in the path of said last mentioned sear arm, when the bolt is not fully in firing position, to be engaged by said last mentioned sear arm to prevent rocking of the sear on its pivot and the release of the hammer from engagement with the first sear arm.

10. In a firearm, a receiver, a cylindrical bolt slidable in said receiver to dispose and hold a cartridge in firing position, mechanism including a spring actuated first member movable axially in said receiver, a pivoted one piece sear having a first arm extending rearwardly and through the receiver from the sear pivot point to engage said first member and releasably retain it against spring action, said bolt having a first relief cut in its rear end, a full diameter portion forward of the first relief cut, and a second relief cut forward of said full diameter portion, said sear having a second arm extending forwardly and through the receiver from the sear pivot point to engage the full diameterportion of said bolt when the bolt is out of position to hold a cartridge in firing position and to prevent swinging of the sear on its pivot to move the first arm to release said first member, and a second member movable to engage and swing said sear in first member releasing position when the second sear arm is out of engagement with the full diameter portion of said bolt, said second member having a portion disposed in the path of movement of said first member to be engaged by the released first member to move the second member out a sear swinging position.

CARL H. BENSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 661,900 Von Zeke et al Nov. 13, 1900 853,438 Browning May 14,

1,041,648 Mauser Oct. 15, 1912 2,296,242 Brewer Sept. 22, 1942 2,377,737 Williams June 5, 1945 2,381,521 Shepherd et a1. Aug. '7, 1945 2,422,854 Reising June 24, 194

cartridge firing 

